Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.
Eur Rev Med Pharmacol Sci. 2019 Jan;23(2):740-748. doi: 10.26355/eurrev_201901_16888.
Dysfunction of the microRNA (miRNA) network is a major regulator in neurological diseases. However, little is known about the functional significance of miRs in ischemic brain injury. This study was designed to investigate the functional behaviors and regulatory mechanisms of miR-196a in ischemic brain injury.
Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in rats. The expression levels of miR-196a and HMGA1 were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), Western blotting, and/or immunocytochemistry. The role of miR-196a in cerebral infarction and brain cell apoptosis was determined by infarct volume estimation and Transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assay, respectively. Bioinformatics software and Luciferase analysis were used to predict and confirm the targets of miR-196a.
The results showed that the miR-196a expression was significantly increased in rat brain after MCAO and in cultured neonatal rat cortical neurons after oxygen-glucose deprivation (OGD). Pretreatment with antagomiR-196a by intracerebroventricular markedly reduced the miR-196a mRNA and HMGA1 protein of the brain in rats subjected to MCAO. Notably, the knockdown of miR-196a could protect MCAO rats against cerebral infarction and brain cell apoptosis. In the OGD model, apoptosis and miR-196a expressions were inhibited, while High-Mobility-Group-A1 (HMGA1) levels were increased in cortical neurons in a time-dependent manner. Moreover, HMGA1 was the target gene of miR-196a. MiR-196a overexpression promoted OGD-induced cortical neurons apoptosis possibly through negative regulation of HMGA1.
These findings indicated a crucial role of miR-196a in regulating infarct volume and neuronal cell death under cerebral ischemia, thus offering a new target for the development of therapeutic agents against ischemic brain injury.
miRNA 网络功能障碍是神经疾病的主要调控因子。然而，miR 在缺血性脑损伤中的功能意义知之甚少。本研究旨在探讨 miR-196a 在缺血性脑损伤中的功能行为和调控机制。
采用大脑中动脉闭塞（MCAO）法诱导大鼠脑缺血。通过定量实时聚合酶链反应（qRT-PCR）、Western blot 和/或免疫细胞化学检测 miR-196a 和 HMGA1 的表达水平。通过梗死体积估计和转移酶介导的脱氧尿苷三磷酸生物素尼克末端标记（TUNEL）测定分别确定 miR-196a 在脑梗死和脑细胞凋亡中的作用。生物信息学软件和荧光素酶分析用于预测和验证 miR-196a 的靶标。
结果表明，MCAO 后大鼠脑和氧葡萄糖剥夺（OGD）后培养的新生大鼠皮质神经元中 miR-196a 表达明显增加。侧脑室预先给予 miR-196a 拮抗剂可显著降低 MCAO 大鼠脑内 miR-196a mRNA 和 HMGA1 蛋白。值得注意的是，miR-196a 的敲低可防止 MCAO 大鼠发生脑梗死和脑细胞凋亡。在 OGD 模型中，皮质神经元的凋亡和 miR-196a 表达呈时间依赖性抑制，而高迁移率族蛋白 A1（HMGA1）水平升高。此外，HMGA1 是 miR-196a 的靶基因。miR-196a 过表达可能通过负调控 HMGA1 促进 OGD 诱导的皮质神经元凋亡。
这些发现表明 miR-196a 在调节脑缺血时的梗死体积和神经元细胞死亡中起关键作用，为开发治疗缺血性脑损伤的治疗药物提供了新的靶点。
